This invention concerns a process for monitoring and/or regulating the cloth tension of a length of cloth processed on a cylinder napping machine whereby the napping machine has pile rollers and/or counterpile rollers on the jacket of the cylinder which subject the cloth to pile-raising energy and/or counterpile-raising energy.
In addition, this invention also concerns the napping machine for carrying out the process according to this invention with pile rollers and/or counterpile rollers on the jacket of the cylinder, a feed roll at the cloth feed end plus a delivery roll at the cloth delivery end.
For effective napping of cloth such as woven or knit fabrics, double-action napping machines are generally used, whereby the napping rolls on the jacket of the cylinder are designed as pile rollers and counterpile rollers with wire card clothing. Wires of the pile rollers generally point in the direction in which the fabric travels over the cylinder, and the wires on the counterpile rollers point in the opposite direction. The cloth is effectively napped, i.e., the fibers of the fabric are raised away from the base of the fabric by means of an alternating arrangement of pile rollers and counterpile rollers. However, this results in a loss of tension on the cloth between one pile roller and the next counterpile roller in the direction of feed of the cloth, and there is tension on the cloth between one counterpile roller and the next pile roller. With known napping machines, it is extremely difficult to find the proper balance between pile-raising energy and counterpile-raising energy. Either the cloth is not napped enough, so several processing passages are required to achieve the desired napping effect, or a high ratio of counterpile-raising energy to pile-raising energy can lead to undesirably extreme mapping, damage or even tearing of the cloth might occur in the extreme case. In addition, however, the cloth tension prevailing over the entire cylinder also has an influence on the pile-raising energy and counterpile-raising energy because if the tension is too low, the fabric is transported over the napping rolls practically without contact, but if the tension is too high, too much stress would be placed on the cloth. Processing of highly stretchable cloth is especially problematical with known napping machines because such cloth can undergo an elongation of more than 100% in processing. Optimum processing of cloth on cylinder napping machines thus depends on the amount of pile-raising energy and counterpile-raising energy as well as the total tension on the cloth on the cylinder. However, it is difficult even for trained and experienced personnel to always find the optimum processing parameters especially when it is necessary to process different types of cloth with different properties in succession.
This invention is therefore based on the goal of creating a process whereby monitoring and/or regulation of cloth tension can be automated in order to optimize processing. Furthermore, a cylinder napping machine is described for carrying out this process, whereby the cloth is automatically kept at the optimum tension and is also exposed to the optimum pile-raising energy and/or counterpile-raising energy, but is nevertheless simple in design and thus economical.